The Global Virtual Network Service (GVNS) is a multi-network international service proposed by the International Telecommunications Union (ITU). GVNS allows service providers to offer subscribing customers a service with features and functionality similar to that of a private network without requiring the customers to purchase and manage the networks. GVNS provides these private network functions to users at geographically dispersed international locations while minimizing the need for dedicated network resources. The GVNS service will utilize an inter-connection between two respective international switching centers (ISCs) using the Public Switched Telephone Network (PSTN).
The ITU has developed a series of standards to define the GVNS, including GVNS Configuration 2 (C2) and GVNS Configuration 3 (C3). These series of standards reflect increasingly complex versions of the service.
The existing GVNS C2 configuration has several limitations. For example, the existing GVNS C2 configuration can utilize only the so-called Called Party Number (CdPN) to carry limited GVNS service-related information. The number of digits available for end-users, network applications and specific service applications is restricted to the length of the CdPN. Thus, the originating carrier information cannot be efficiently obtained by the CdPN alone.
Furthermore, the GVNS C2 configuration cannot be used to provide transit service directly. Transit service routes calls originating in one foreign country to a destination in another foreign country while passing through a third country service provider. Using the GVNS C2 configuration, indirect addressing at the switch located in the intermediate third country is needed to interpret the call destination.
GVNS C3 will overcome many of the limitations associated with GVNS C2 by transporting GVNS-specific parameters in International Consultative Committee for Telegraphy and Telephony (CCITT) #7 ISUP protocol, an international common-channel signaling standard. In addition to passing expanded routing information, GVNS C3 will also pass additional information in the GVNS C3 parameters, including service-specific information. Implementation of the GVNS C3 service, however, presents several difficulties. Although GVNS C3 parameters are compatible with CCITT #7 ISUP protocol, they are not compatible with the Common Channel Signaling System 7 (CCS7) ISUP protocol, a North American common-channel signaling standard. Thus, an international call to, from or through North America must be translated from GVNS C3 parameters in CCITT #7 ISUP protocol to CCS7 ISUP protocol, or vice versa.
Translating CCITT#7 ISUP protocol to or from CCS7 ISUP protocol should be performed in a cost effective and efficient manner. In the case of an outbound international call from a North American origin, populating the GVNS C3 parameters at the location from where each call originates is not the most cost effective or efficient approach. Cost effectiveness and efficiency also discourages transporting the GVNS C3 parameters from the call originating location, through the CCS7 network, and to the foreign network destination. Similarly, in the case of a call inbound from a foreign location, cost effectiveness and efficiency discourage transporting the GVNS C3 parameters from the edge of the CCS7 network, through the CCS7 network, to the call destination.
Thus, interoperability problems will exist between the carriers that implement the GVNS C3 service and those carriers that refrain from implementing GVNS C3 and continue to use GVNS C2.